A compactor is adapted to compact a material to a desired density. The compactor may be a landfill compactor or a soil compactor. Examples of applications include, but not limited to, construction sites to prevent natural settling of the ground, landfill sites to compact the landfill waste into a small volume as possible, and blacktop roads and parking lots, to prevent settling of the blacktop, and hence prevent future cracking of the road or the parking lots.
The landfill compactor is propelled by a powertrain having an engine connected to a transmission via a torque converter. One characteristic of torque converters is their ability to multiply torque when there is a difference between the input speed to the converter from the engine and the output speed of the converter to the transmission. Some torque converters also include a locking mechanism that transfers engine speed directly to the transmission with no substantial torque multiplication or speed variation. The landfill compactor may be desired to run in a second gear transmission ratio for efficient fuel management. Further, the use of torque converter in the second gear transmission ratio may overheat the torque converter due to heavy loading conditions and may lead to inefficiency of the landfill compactor. In the second gear, speed of the engine may limit for efficient compacting of the material.
U.S. Pat. No. 4,414,863 discloses a controller including a microprocessor for automatically shifting a transmission and selectively locking and unlocking a torque converter connecting the engine with the transmission. The controller has both manual and automatic modes of operation. In the automatic mode, one of three different shift patterns is automatically selected depending on the condition of a transport/loading mode switch and a throttle position switch. Transmission output speed is monitored and downshifts are prevented when the output is accelerating.